$249 Nest Thermostat?

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Most thermostat wiring is going to be a two wire switch, r to w, and most programmable electronic stats run with AA batteries. Very rarely will the C, common, of the stat circuit be run to the stat location.

I did some troubleshooting of a Nest stat, homeowner install, gadget freak early adopter. He had tried to troubleshoot it and was telling me I had to run the C wire to all the stats, per the factory support.

I believe the Nest self powers from a small parasitic current draw between the R and W wires. Nest says the stat is rated for two wire, R to W, installs, but says if you have trouble, to run the C wire to the stat. I tried to get the operating characteristics from the factory, to see if the system was suitable and working or not, but they like to treat it as a black box, no internal details.

It has to be charging an internal battery or extra large capacitor to run the processor and wifi. It must be self powering from the R to W in series with the heat relay coil and remaining idle most of the time with bursts of processor and wifi to minimize power consumption.

He had a bad stat that was really flaky, but the factory diagnosed it as a power issue and recommended running the C to the stat. I beat on them and said no, your rating says the stat will work on the typical two wire, R to W, application. Once it was diagnosed as a bad stat, as far as I know the factory swapped the unit. It was a new install.

My only concern would be the longevity of the internal rechargeable battery. Usually batteries are toast after five years, and if that causes the Nest to fail, I would say they have a design flaw. Thermostats are critical equipment. They would need to have an expected lifetime more than 25 years to be saleable. The factory would not give any information on this when I asked. Their fallback position was to say, run the C wire to the thermostat for power issues, which is not practical for old work installs.

Other than that, the wifi internet access, software, and learning program are features some people will use. My impression is their marketing is a little ahead of the product. They could not answer how the nest internally stores power or how long that will last (they know power is an issue but most application will only have R and W at the stat). If they try to say Nest will save money with the learning, occupied / unoccupied temp setback, in practice most users will not make that work.

The biggest selling point would be the internet accessible remote monitoring and adjustment, for users that need that. They could be a good company in the future, but it's still early in the development of their products.
 
Service Calls

Service Calls

I'm an HVACR veteran of close to 30 years. I would not give a thin dime for this type of " Tek."
While still in the thick of medium commercial service in Dallas, TX. I had to carry a Library to deal with all the " then " programmable thermostats I ran into.
Programmable stats = way more service calls than before they came into widespread use.
Most people do not use their functionality because they are too complicated, even for service Techs. Also we have to deal with an increasing number and complexity of types as we move forward in time. They do not do what they are supposed to do and moreso, just create problems where none would have existed before. They can have " some " merit in commercial settings if they are chosen and managed wisely, but they require savvy to get the gains.
Any style that requires batteries are useless. I always use " powered " models as they are way more reliable.
The unit described is produced for neurotic people.
The proliferation of all manner of wireless Technology is a bad idea. Especially if it operates in the microwave range.
 
Being able to set the temperature remotely with your smart phone is just a feature for those tech savvy guys to be able to do just because the technology is available. Even some of those people move on to something else after a while and will eventually no longer use that feature.

If I am gone for a long period, so what if I have to wait for the house to warm up, chances are I came in from the cold and it still feels warm at the time.

If I am gone for a short period, I probably only turned temp down (if I even turned it down) five degrees or less. Again, the wait for the house to warm up is not going to be the major event of the day (I hope).

Many people make a bigger issue of this than it really is.

What did our ancestors do when they woke up in the morning and found fire was out and the house was cold? My guess is they started another fire. :roll:
 
If the technology is there, we will use it and we will learn something new.
 
kwired said:
What did our ancestors do when they woke up in the morning and found fire was out and the house was cold? My guess is they started another fire. :roll:
Click to expand...

That's funny. That's exactly the setup I have, want heat, make fire. But it's a state of the art cordwood gasification boiler. Put the wood in, light it, and walk away.

I am planning, playing around with, an AB micro 800 smart relay to automate several things, sources available, DHW priority, and heat scavenging with DHW priority. The micro 800 has 4 analog inputs and I've been researching, surfing the web, for the method of getting the LM35 semiconductor temp transmitter, 0 to 1 volt output, into the micro 800, 0 to 10 volt analog input. Looks like I should be able to do it with an op amp, but I have not found the standardized how to, and have other things I'm supposed to be doing. Pretty sure I've found an op amp that will work, so I'll be spending $150 for a smt soldering station and $20 for parts (two temp sensors for storage available and DHW return water priority).

Once the control is automated, I will forget about it. Until I want heat again, then it will be add fuel and light it, walk away and forget about it.

Web access and HMI would be nice with the boiler control, but not $1000 more, nice, which is what four Nests would be, like the next step up in web access PLC's.
 
Sierrasparky said:
Wifi stats are great , use a C wire and be safe.
Click to expand...

I agree, things are much easier since I've installed my Honeywell Wifi t-stat. The Honeywell requires a connection to a C but they don't tell you if it's a C from the heat or cooling. It only works on the cooling. :thumbsdown:
 
shortcircuit2 said:
I have a customer asking about the Nest thermostat. Has anyone here installed them yet? What do you think about them? They have Smoke/CO alarms now too...

http://nest.com/thermostat/life-with-nest-thermostat/
Click to expand...

i put one in last winter. zero complaints, works well.
significant fuel savings. i didn't think it'd make that
much difference. it did. i put it in at end of jan.

have two of my customers who use them... works well
for them too.

01-13 was 88 hours heating.
02-13 was 67
03-13 was 28
04-13 was 08

nest also totals data and calcs how much the
stat has saved you, allowing for ambient in
your area. it pretty much paid for itself last
winter for me.
 
Maybe I'm just getting old and half crusty...

I found the introduction to this device oh scary, maybe even creepy.

Seasonally, I am late to turn on either the heat or the A/C.

My one cat will be sitting all day in the living room and demanding heat or A/C,
I don't think so, and I know I'm not going to program the T-stat around this animal either.

Wait till we hear about the break-ins cause this thing is reporting to much.

I just don't need to be that connected...
 
Fulthrotl said:
i put one in last winter. zero complaints, works well.
significant fuel savings. i didn't think it'd make that
much difference. it did. i put it in at end of jan.

have two of my customers who use them... works well
for them too.

01-13 was 88 hours heating.
02-13 was 67
03-13 was 28
04-13 was 08

nest also totals data and calcs how much the
stat has saved you, allowing for ambient in
your area. it pretty much paid for itself last
winter for me.
Click to expand...

Why do we care much about how many hours of heating there was?

If you want to maintain a specific temperature, it will take a specific amount of energy to do so depending on other factors like outdoor temperature, thermal insulation, and heating unit efficiency. The most a thermostat will do to save energy is automatically adjust setpoint to use less energy when it is desired or acceptable to change the set point.

Now if the thing is to complicated for the user and they have to call a service guy periodically, to solve issues with it, then the service calls can easily cost more than the additional energy used by a system controlled by a thermostat that does not automatically set back.
 
__dan said:
That's funny. That's exactly the setup I have, want heat, make fire. But it's a state of the art cordwood gasification boiler. Put the wood in, light it, and walk away.

I am planning, playing around with, an AB micro 800 smart relay to automate several things, sources available, DHW priority, and heat scavenging with DHW priority. The micro 800 has 4 analog inputs and I've been researching, surfing the web, for the method of getting the LM35 semiconductor temp transmitter, 0 to 1 volt output, into the micro 800, 0 to 10 volt analog input. Looks like I should be able to do it with an op amp, but I have not found the standardized how to, and have other things I'm supposed to be doing. Pretty sure I've found an op amp that will work, so I'll be spending $150 for a smt soldering station and $20 for parts (two temp sensors for storage available and DHW return water priority).

Once the control is automated, I will forget about it. Until I want heat again, then it will be add fuel and light it, walk away and forget about it.

Web access and HMI would be nice with the boiler control, but not $1000 more, nice, which is what four Nests would be, like the next step up in web access PLC's.
Click to expand...

Still have not solved the real problem though... how is that wood going to get loaded into the boiler when you are away? Maybe with the prototype Honda robot?
 
mtfallsmikey said:
Still have not solved the real problem though... how is that wood going to get loaded into the boiler when you are away? Maybe with the prototype Honda robot?
Click to expand...
Natural gas, POCO supplied electricity, or some kind of solar heated system don't generally run out, they may break down, but other fuel sources do need replenished or you will have same thing.:happyyes:
 
mtfallsmikey said:
Still have not solved the real problem though... how is that wood going to get loaded into the boiler when you are away? Maybe with the prototype Honda robot?
Click to expand...

The house is superinsulated, 2" XPS foam under the slab and exterior of the foundation, 3" polyiso nailbase under the siding. I would have put foam under the footing if I had known you could do that. Because of the insulating system, the house is in the range of freeze proof even with no heat for months in winter. If the house drops below 55 F, it gets some heat and moderation of the temperature from the foundation.

The present system runs the basement radiant slab as storage for the wood boiler. The basement slab runs ~ 90 F on the IR gun at temp and there is near zero call for heat from the rest of the house. I've gone away for three days in the winter, the basement slab drops to ~ 72 F and the house drops to ~ 60 F with no heat. It would probably take 4 weeks to drop the house to 32 F in solid 0 F weather with the slabs at temp. 3 cords for the year, heat and DHW, with this system.

Absolutely in a conventional house, with no storage and double the heat loss, you may have freeze risk in a week of cold weather.

The existing oil boiler is plumbed to the loads in parallel, and code requires the auto central heat source. Everything except the final wiring is done and ready to fire. OAT reset with warm weather shutdown is done ( two, one for each boiler). When the final is done, the oil will fire on a low limit stat ~ 55 F inside the house and enable on, hand off to the regular house radiant stats.

I would also have to put more oil in the tank, which I have no plans for.

In relation to the Nests, the guy was probably burning 1100 gal oil annually for his conventional, older renovated expensive house. It was too late to install super insulation. I was recommending the $20,000 installed Froling P4 pellet boiler to replace his oil burner. He was being quoted $25.000 to replace it with propane, which is comparable to oil in fuel cost.

The Froling pellet boiler with OAT reset of the baseboard zones would have made the Nests unnecessary. He would have to directly empty the ash once or twice seasonally, maybe brush the firetubes once a year, load the fuel hopper or go with a bulk delivery system, but there would be no need to watch the boiler run over the internet. Though it is a great feature, I had other plans for his money.
 
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